The present invention relates to a method for successively feeding flat products on to a user machine, in particular a packing machine.
The present invention may be employed to advantage by the food industry for forming groups of sweets, biscuits or similar products upstream from a packing machine.
The food industry is known to employ manufacturing, e.g. sweet manufacturing, machines at the output of which the flat products coming off the machine are fed in bulk on to a device by which they are fed on to a wrapping machine.
Said feed devices, such as the one referred to in Italian patent application No. 3481A/88, U.S. Pat. No. 5,058,725 being based thereon, usually comprise an input container designed to receive the products in bulk and feed them, still in bulk, on to a distributor usually consisting of a vibratory tray, the output end of which communicates with the input end of an aligning device usually comprising at least one vibratory channel. Said channel slopes slightly downwards, and provides for lining up the products in a neatly arranged row and feeding them successively on to a pocket type conveyor at the packing machine input through a transfer device designed to arrange the products in such a manner as to form, on the input conveyor, groups of products, each comprising a continuous sequence of a given number of products arranged on edge and substantially side by side.
One of the major drawbacks of known feed devices of the aforementioned type is the difficulty encountered in continually adapting product flow to the frequently variable output speed of the packing machine, and in obtaining, for any output speed and at least along the output end portion of said vibratory channel, a continuous line of products arranged side by side and contacting one another. Such a product arrangement, at least immediately upstream from the transfer device input, is essential for filling all the pockets on the packing machine input conveyor, and so preventing the formation and subsequent rejection of incomplete groups. To overcome this drawback, various steps have been taken on known feed devices of the aforementioned type, such as providing the vibratory channels with sophisticated electronic control equipment designed to vary the vibration frequency of the channels in such a manner as to adapt the traveling speed of the products to the output speed of the packing machine; and employing relatively long vibratory channels enabling any gaps between adjacent products to be gradually closed as the products travel along the channels.
Both the above provisions, however, have simply resulted in relatively cumbersome, high-cost, poorly reliable feed devices, which nevertheless fail to provide for fully eliminating the gaps between adjacent products in the vibratory channels. Also because continual adjustment of the vibration speed of the channels and, consequently, of the traveling speed of the products along the same, in itself results in the formation of gaps between adjacent products. Moreover, the extra length of the vibratory channels automatically increases the time the products are subjected to vibration and, consequently, susceptible to breakage.
As yet, it is practically impossible to run a known feed device of the aforementioned type without the continual assistance of an operator for manually closing any gaps between adjacent products traveling along the vibratory channels, and picking out any broken products which might impede throughout.